1. The problem statement, all variables and given/known data A roller coaster car has a mass of 500 kg when fully loaded with passengers.(a)If the vehicle has a speed of 20.0 m/s at point A, what is the force exerted by the track on the car at this point?(b)What is the maximum speed the vehicle can have at B and still remain on the track? 2. Relevant equations ac = v^2/r F = m*a My Question My problem is not so much how to solve this, I'm rather concerned about centripetal forces in general. For both questions a and b I intuitively know the result of an increased speed, however it doesn't make sense with my mechanical knowledge. For question b, and this will probably solve my issue with question a, if the centripetal force is acting downwards why would an increasing speed and hence stronger downward force result in the train leaving the tracks. I suppose it either has to do something with newtons first law or I'm misunderstanding something about centripetal forces. Another related issue I have is radial acceleration. I know that radial acceleration = - centripetal acceleration but I don't understand the benefit and the implications of this notation.